Efekti polifenola soka od aronije na kardiovaskularne faktore rizika i masnokiselinski profil u animalnoj i humanoj studiji

Abstract

Kardiovaskularne bolesti su vodeći uzrok smrtnosti u Srbiji i svetu. Svakodnevni dijetarni unos voća i povrća može smanjiti učestalost nastanka ovih oboljenja. Namirnice biljnog porekla sadrže različite komponente sa antiinflamatornim i antioksidativnim svojstvima, a među njima su i polifenoli. Ova doktorska disertacija je imala za cilj ispitivanje efekata polifenola soka od aronije na faktore rizika za kardiovaskularne bolesti i masnokiselinski profil pacova Wistar soja i ljudi. U obe studije analiziran je uticaj: 1) soka od aronije (sa 1177,11 mg/100 mL polifenola izraženih u ekvivalentima galne kiseline); 2) placeba bez polifenola; 3) soka od aronije razblaženog placebom (sa 294,28 mg/100 mL polifenola izraženih u ekvivalentima galne kiseline). Animalna studija je trajala pet nedelja tokom kojih je svaka grupa mužjaka Wistar pacova (n = 8) imala neometan pristup, ad libitum, jednoj od tri tečnosti. Humana studija je trajala četiri nedelje, tokom kojih su ispitanici (n = 84), podeljeni u tri grupe, dnevno pili po 100 mL jednog od pića. Svaka grupa je imala povišene vrednosti sledećih parametara: koncentracije LDL holesterola u serumu, indeksa telesne mase, obima struka i sistolnog pritiska. Procenjeno je da je prosečan dnevni unos polifenola bio 557 mg za grupu pacova koja je pila sok od aronije, odnosno 120 mg za onu koja je unosila razblaženi sok od aronije. Na kraju studije je koncentracija LDL holesterola u plazmi bila manja, a procentualna zastupljenost vakcenske kiseline veća u fosfolipidima i plazme i jetre, kod pacova koji su unosili više polifenola, u poređenju sa onima koji su pili placebo. Rezultati humane studije pokazali su smanjen krvni pritisak ispitanika sve tri grupe u poređenju sa početnim vrednostima, ali bez razlike između grupa. Došlo je do smanjenja vrednosti oksidovanog LDL-a kod ljudi koji su pili sok od aronije, u poređenju sa početnim vrednostima, ali bez statistički značajne razlike u odnosu na one koji su pili placebo. Unos oba soka sa polifenolima je smanjio procentualnu zastupljenost ukupnih n-6 polinezasićenih masnih kiselina i povećao udeo zasićene palmitinske kiseline u fosfolipidima plazme, u poređenju sa početkom studije i placebom. To je pokazano i poređenjem samo muškaraca tri grupe. Nije bilo povezanosti varijanti gena desaturaze masnih kiselina 2 (rs174576, rs174593, rs174616) sa efektima polifenola soka od aronije. Efekti polifenola aronije na masne kiseline plazme pacova Wistar soja nisu pokazani kod ljudi, stoga se na osnovu promena u masnokiselinskom profilu jetre pacova ne može pretpostaviti kakve se promene očekuju u jetri ljudi usled dijetarnog unosa ovog voća. Zbog odsustva statističke značajnosti u poređenju sa placebo grupom, smanjenja krvnog pritiska i koncentracije oksidovanog LDL-a u humanoj studiji se ne mogu pripisati dejstvu polifenola. Naši rezultati ukazuju da su polifenoli komponenta soka od aronije koja je potrebna za promene zastupljenosti n-6 polinezasićenih masnih kiselina i palmitinske kiseline fosfolipida plazme ljudi, da je za to dovoljna količina od 294 mg ekvivalenata galne kiseline, a moguće je da je ovo dejstvo polno-specifično. Neophodno je dalje ispitati efekte unosa polifenol.

Cardiovascular diseases are the leading cause of death in Serbia and the world. Daily dietary intake of fruits and vegetables can reduce the incidence of these diseases. Foods of plant origin contain various components, with anti-inflammatory and antioxidant properties, and among them are polyphenols. This doctoral dissertation aimed to examine the effects of chokeberry juice polyphenols on risk factors for cardiovascular diseases and fatty acid profile of Wistar rats and humans. In both studies was analyzed the influence of: 1) chokeberry juice (with 1177.11 mg/100 mL of polyphenols expressed as gallic acid equivalents); 2) polyphenol-free placebo 3) chokeberry juice diluted with placebo (with 294.28 mg/100 mL of polyphenols expressed as gallic acid equivalents). The animal study lasted for five weeks during which each group of male Wistar rats (n = 8) had unrestricted access, ad libitum, to one of the three liquids. The human study lasted for four weeks, during which subjects (n = 84), divided into three groups, drank 100 mL of one of the drinks per day. Each group had elevated values of the following parameters: serum LDL cholesterol concentrations, body mass index, waist circumference and systolic pressure. The average daily intake of polyphenols was estimated to be 557 mg for the group of rats that had been drinking chokeberry juice, and 120 mg for the group that had been ingesting diluted chokeberry juice. At the end of the study, the concentration of LDL cholesterol in plasma was lower, and the percentage of vaccenic acid was higher in plasma and liver phospholipids, in rats that ingested more polyphenols, compared to those who drank placebo. Results of the human study showed decreased blood pressure of the subjects of all three groups compared to the initial values, but without a difference between the groups. There was a decrease in oxidized LDL levels in people who drank chokeberry juice, compared to baseline values, but there was no statistically significant difference from those who drank placebo. Intake of both polyphenol juices reduced the percentage of total n-6 polyunsaturated fatty acids and increased the percentage of saturated palmitic acid in plasma phospholipids, compared to the beginning of the study and placebo. That was also shown by comparing only men of the three groups. There was no association between the fatty acid desaturase 2 gene variants (rs174576, rs174593, rs174616) and the effects of chokeberry juice polyphenols. The effects of chokeberry polyphenols on Wistar rat plasma fatty acids have not been shown in humans, therefore, based on changes in the fatty acid profile of rat liver, it cannot be assumed what changes are expected in human liver due to dietary intake of this fruit. Because of the lack of statistical significance in comparison with the placebo group, the reduction in blood pressure and oxidized LDL concentration in the human study cannot be attributed to the effect of polyphenols. Our results indicate that polyphenols are the component of chokeberry juice needed for changes in the percentage of n-6 polyunsaturated fatty acids and palmitic acid in human plasma phospholipids, that the amount of 294 mg of gallic acid equivalent is sufficient, and this effect may be gender-specific. It is necessary to further investigate the effects of chokeberry juice polyphenol intake in prevention of cardiovascular diseases via the influence on fatty acid profile.